Having had a few different RV's, the cost to maintain depends on how many miles you drive per year, and how much of the work you can do yourself. I budget $1,200 per year for annual maintenance, oil change, oil and fuel filters, DOT Inspection, which is around $500 a year, so I have $700 put back for other scheduled stuff, which I may or may not spend that year, and let it accrue into the next year. I also put back $400 a year for tires. I have owned the Coach 2 years, and this next May will be year 3 and I have $2,200 sitting in an account that has not been spent yet, and I will deposit another $1,200 in January. This year I will need to have the coolant drained, thermostat replaced when it goes in for it's annual servicing. I drive less than 10K per year, drive it year around, so I service it every month in May. If you drive more, you spend more. Also some expenses I don't count, roof sealing every year, so far no cracks or leaks, so no expense, but eventually I will need to reseal it, or eternabond it, and this expense you will have with a TT or 5'er.
I have a separate fund for camping and fuel.